Reactions Of Tritium Atoms Research Articles

Effect of Graphene Oxide and Carbon Nanotubes on the Reaction of Tritium Atoms with Dalargin

Effect of carbon substrates materials (graphene oxide, reduced graphene oxide, single-walled carbon nanotubes) on the result of tritium introduction into dalargin peptide was studied by the thermal activation method. It was shown that, when dalargin is deposited onto carbon substrates, the distribution of tritium over amino-acid residues strongly changes as compared with a thick target deposited directly onto glass walls of a vessel. It was demonstrated that, when dalargin is deposited onto the carbon materials studied, the content of tritium in phenylalanine substantially increases, which indicates that the isotope exchange reaction occurs by the electrophilic mechanism. It was also found that the content of tritium in other amino-acid residues substantially changes, which is due to the difference between the structures of adsorption layers of the peptide, formed n the carbon materials under consideration.

Nonequilibrium processes in reactions of hot tritium atoms with cooled solid targets. Influence of the atomizer temperature on formation of labeled substances

A system consisting of a cold target and “hot” atoms generated by dissociation of tritium on a tungsten wire was studied with the aim to determine conditions for preparing tritium-labeled organic compounds with the maximal radiochemical yield. The influence of the atomizer temperature on the result of the reaction of tritium atoms with amino acids and tetraalkylammonium bromides was studied; homological series of the substrates were examined with the aim to evaluate the contributions of functional groups and hydrocarbon tail to the processes occurring in the target. The dependence of the yield of the labeled parent compound on the atomizer temperature varied in the range 1600–2000 K was determined. The rates of decarboxylation and deamination sharply grew with increasing temperature of the tungsten wire. The highest yield of labeled amino acids was attained at an atomizer temperature of 1800–1900 K, and at higher temperature their yield decreased. The difference between the activation energies of the elimination of the carboxy and amino groups and of the isotope exchange of hydrogen for tritium in the C-H bond appeared to be 93 and 59 kJ mol−1, respectively. For alkyltrimethylammonium bromides with the alkyl radicals C12H25, C14H29, and C16H33, the yield of the labeled parent compound reached 80–90% and was virtually independent of the atomizer temperature. The capability of tritium atoms to penetrate into the targets was evaluated. For the exponential model of the attenuation of the flow of tritium atoms inside the target, the attenuation factor for freeze-dried amino acids and alkyltrimethylammonium bromides as targets was 1.8 nm−1.

Probability of the reaction at the first collision with polyethylene of tritium atoms generated by thermal activation

The influence of the experimental conditions on the probability of the reaction of tritium atoms generated in the gas phase by thermal dissociation of tritium on a tungsten filament (thermal activation) with hydrocarbons in a solid target was examined. Experiments were performed with polyethylene films placed in a special case with a calibrated slit in the center of the top lid. For tritium atoms reaching the target without energy loss, the probability of the reaction at the first collision with the hydrocarbon matrix cooled to 77 K decreases from 18 to 2.5% with a decrease in the atomizer temperature from 2000 to 1660 K. For tritium atoms preliminarily thermalized in the gas phase to 77 K, the probability of the reaction at the first collision is so low that it cannot be measured with our experimental technique. Nevertheless, even at 77 K tritium atoms can react with the target, yielding the compound labeled at the C-H bonds.

Notizen: Experimental Evidence for 1,2-Fluorine Atom Migration in Tritiated 1,1,2-Trifluoroethyl Radical

Tritiated compounds containing 2,2,2-trifluoroethyl groups were formed by the reaction of tritium atoms with trifluoroethylene. The result can be accepted as definitive evidence for a 1,2-fluorine atom migration occurring in the reaction intermediate, tritiated 1,1,2-trifluoroethyl radical.

High-Energy Reactions of Tritium Atoms with Methane and Silane

High-Energy Reactions of Tritium Atoms with Methane and Silane

Reaction of tritium atoms with unsaturated compounds

AbstractThe reaction of tritium atoms with unsaturated compounds was shown to proceed both by addition to the double bond yielding the reduced product as well as by tritium/hydrogen exchange resulting in labeled parent. Reduction occurred to varying degrees in all cases investigated but appears to be far less significant than in Wilzbach labeling. The addition/substitution ratio producing labeled products for oleic acid was 2.6(compared to 24.4 by Wilzbach) for the unsaturated amino acids 3,4‐dehydro‐D,L‐proline and L‐2‐amino‐4‐(2′‐aminoethoxy) trans‐3‐butenoic acid was 12.8 and 11.6 respectively and for morphine (resulting in 6,7‐dihydromorphine) only 0.02.

Excitation functions for the reactions of tritium atoms with HF and DF

Reaction and dissociation cross sections for the interaction of tritium atoms with HF and DF in the energy range 20–3000 kJ mol–1 are evaluated by classical trajectory methods. Integrated cross sections for the primary reaction products and approximate energy loss parameters are discussed.

Reactions of Tritium Atoms with Tritium-Labeled Isopropyl Radicals at 63°K1

Reactions of Tritium Atoms with Tritium-Labeled Isopropyl Radicals at 63°K¹

602. Reaction of tritium atoms with films of solid ethylene. Disproportionation and combination of ethyl radicals at 63°K: K W Watkins and H C Moser, J Phys Chem, 69, March 1965, 1040–1044

602. Reaction of tritium atoms with films of solid ethylene. Disproportionation and combination of ethyl radicals at 63°K: K W Watkins and H C Moser, J Phys Chem, 69, March 1965, 1040–1044

Reaction of Tritium Atoms with Films of Solid Ethylene. Disproportionation and Combination of Ethyl Radicals at 63°K.1

Reaction of Tritium Atoms with Films of Solid Ethylene. Disproportionation and Combination of Ethyl Radicals at 63°K.¹

Mechanisms for the Reactions Following Radiative Neutron Capture in Liquid Organic Halides

Summary The available data together with some recent work done by the author, have been reconsidered with regard to establishing a unified approach to the chemistry of hot atoms. It was found that the "Impact Model", originally proposed for the hot reactions of tritium atoms in gases, can also give an adequate picture for the reactions of activated halogen atoms in liquid organic halides.